North American analysis and synthesis on the connectivity of geographically isolated wetlands to downstream waters
Wetlands occur along gradients of hydrologic and ecological connectivity and isolation, even within wetland types (e.g., forested, emergent marshes) and functional classes (e.g., ephemeral systems, permanent systems, etc.). Within a given watershed, the relative positions of wetlands and open-waters along these gradients influence the type and magnitude of their chemical, physical, and biological effects on down-gradient waters. In addition, the ways in which wetlands connect to the broader hydrological landscape, and the effects of such connectivity on down-gradient waters, depends largely upon climate, geology, and relief, the heterogeneity of which expands with increasing scale. Developing an understanding of connectivity between and among uplands, wetlands, and down-gradient waters, as well as ascertaining the influence of climate, geology, relief, spatial distribution, and other phenomena on connectivity has thus emerged as an important focal research area for science with significant implications for the integrity of aquatic systems. This proposal will organize a comparison and synthesis of wetland connectivity across regional landscapes in North America. The two primary objectives are to: (1) Quantify and model hydrological connectivity among wetlands and between wetlands and down-gradient surface waters across specific ecoregional, physiological, and/or physiographic provinces, and (2) Identify emergent properties of wetland connectivity across different landscape settings and scales to determine factors controlling connectivity, including climate, geology, and relief as well as spatial distributions of wetlands. To reach these objectives, our working group will develop an organizing conceptual framework for the research that accounts for multiple dimensions of possible connectivity (e.g., longitudinal, lateral, vertical, and temporal) as well as landscape, soil, climatic, and other factors controlling connectivity across focal regions. We will use existing spatial datasets to develop and quantify novel spatial indicators of wetland connectivity on the landscape across different regions. We will further develop and apply geostatistical and hydrological modeling approaches to discern the controls on wetland connectivity and effects of this connectivity on down-gradient hydrology. The results from this Powell Center working group will provide unique insights on the connectivity of wetlands and identify areas where additional scientific research is required to better understand these important components of the terrestrial and aquatic hydroscape.
David M Mushet